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Glossary

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4. Glossary:


Acetaminophen : component of many over-the-counter pain killers (such as Tylenol*) and cold medications. It reduces fever and sensitivity to pain.

Acute : short-term infection

ALT : alanine aminotransferase. This is a type of enzyme normally found in the liver. When liver cells are injured this enzyme leaks into the blood. Therefore, persistently abnormal levels of this enzyme in the blood indicate that the liver may be inflamed or damaged.

Amino acids : nitrogen-containing molecules. Proteins, both in food and in human tissue, are made up of chains of various amino acids. There are 22 known amino acids and the sequence of these amino acids accounts for the distinctive characteristics of each protein.

Analogue : in chemistry, a compound with a structure similar to that of another compound but differing from it with respect to certain components or structural makeup, which may have a similar or opposite action metabolically.

Anemia : decreased ability of the blood to carry oxygen from the lungs throughout the body. This is measured as hemoglobin or red blood cell count.

Antibody : a type of immune protein molecule that is produced when bacteria, a virus or a foreign protein substance, enters your body. A specific antibody is produced against each invader.

Antigen : any substance that stimulates the immune system to produce antibodies. The hepatitis C virus is an example of an antigen.

Antiphospholipid syndrome : A disorder characterized by the autoimmune production of antibodies against cell membrane constituents (proteins and phospholipids) and by venous or arterial thrombosis, or recurrent abortions. The cause of this syndrome and the mechanism of the prothrombic state are not known.

Anti-HCV test : a blood test which looks for and measures antibodies to the hepatitis C virus. A positive anti-HCV result does NOT indicate immunity to hepatitis C. Rather it indicates that you have been exposed to the hepatitis C virus and likely still have the infection.

Antiviral drugs : drugs that work against a virus, such as the hepatitis C virus.

Antiviral : a substance or process that destroys a virus or prevents it from reproducing.

Arterio portal fistula : abnormality where a hepatic artery and a portal vein communicate permanently. Causes can be congenital, traumatic or surgical. Occasionally, the fistula appears to have developed spontaneously.

Ascites : swelling of the abdomen due to an accumulation of fluid. Ascite gonflement de l'abdomen dû à une accumulation de liquide dans le péritoine. Elle peut être importante et plus ou moins gênante, l'apport de sel peut la majorer. Elle peut être diminuée par la prise de médicaments diurétiques et/ou une ponction d'ascite.

AST : aspartate aminotransferase. An enzyme that is normally found in liver cells, that can leak out of these cells and make its way to the blood when liver cells are injured. The ALT is felt to be a more specific indicator of liver inflammation, as AST is also found in other organs such as the heart and skeletal muscle.

Autoimmune : directed against the body's own tissue, e.g. autoimmune hepatitis.

Autologus blood donation : predonation and storage of a patient's own blood a few weeks before elective surgery. This way, if the patient needs a transfusion during surgery they can receive their own blood and not someone else's.

Behcet disease : an inflammatory disease of unknown origin, seldom seen in the West, well known in Turkey and North Africa. The clinical spectrum includes involvement of veins, joints, skin, eyes and gastrointestinal tract. Inferior vena cava thrombosis is frequent. In this disease, the cause of the prothrombic state is still not understood.

Bile : a substance secreted by the liver that helps in the digestion of fats. It is stored in the gall bladder until required.

Bilirubin : a yellow substance formed when red blood cells age and break down. The liver normally breaks down bilirubin for excretion. However, if the liver is not functioning properly bilirubin may accumulate in the blood stream causing jaundice.

Body fluids : any liquid in the body such as blood, urine, saliva, sputum, tears, semen, breast milk or vaginal secretions.

Bone marrow : the inside of bone where blood cells are formed.

Budd-Chiari syndrome : the condition results from the obstruction of the hepatic venous outflow tract, when the obstruction lies between the small intrahepatic veins and the termination of inferior vena cava in to the right atrium.

There are two categories of Budd- Chiari syndrome.

The first one, so called primary Budd-Chiari syndrome, covers the blockade of the venous system due to thrombosis or to a narrowing of the venous wall, whether they are focal or diffuse . In this category Budd Chiari syndrome is explained by a prothrombic state.

In the second category, so called secondary Budd-Chiari syndrome, tumours, parasites or extrinsic compression are responsible for the blockade rather than a primary disease of the veins.

Carrier : a person who has a virus in his/her system but who may not necessarily have symptoms or show signs of illness. This person can, however, pass the virus on to other people and make them sick.

CAT scan : computerized axial tomography. A special kind of x-ray for looking at the soft organs in the body, such as the liver. A three-dimensional image of a body structure is constructed by computer from a series of cross-sectional images made along an axis. Also referred to as a CT scan.

Cholestasis : blockage or suppression of bile flow, from either intrahepatic or extrahepatic causes. blocage ou suppression du débit de la bile dans les canaux biliaires. Les causes peuvent être intrahépatiques ou extrahépatiques. Cette cholestase est mesurée par un bilan sanguin hépatique.

Chronic : long-term infection. Chronic hepatitis C infection persists longer than 6 months and usually for years.

Cirrhosis : scarring of the liver as it attempts to protect itself from inflammation. Blood cannot flow freely through scarred liver tissue and thus the liver cannot perform its normal functions.

Clinical trial : a scientifically controlled study done with human subjects to investigate the effectiveness, safety and ideal dosage of a new drug or treatment.

Combination therapy : use of two or more medications at once. For hepatitis C, combination therapy with interferon and ribavirin is now the standard treatment.

Congenital portocava shunt : abnormal passage of the blood from a portal vein to a vein draining into inferior vena cava due to a congenital defect joining the two veins. This anomaly is present from birth.

Congestion : Abnormal accumulation of blood inside vessels, tissues or organs. A downstream obstacle generating a stasis can explain the congestion. Other reasons can be a congenital vessel dilatation or abnormal exit of blood cells outside damaged vessels.

Contraindication : a specific circumstance when the use of certain treatments could be harmful.

Cryptogenic cirrhosis : cirrhosis of unknown or hidden origin.

CT scan : computerized tomography scan. This is a special kind of three-dimensional x-ray used for looking at the soft organs in your body, such as the liver. Also referred to as a CAT scan.

Decompensation : failure of the liver to compensate for damage or injury, resulting in a decrease in liver functions.

Diagnosis : determining the presence of a specific disease or infection, usually based on evaluating a patient's symptoms and results from laboratory tests.

Dialysis : a treatment for kidney disease that removes waste from blood. Used when the kidneys cannot perform their normal waste removal function (Also called hemodialysis).

Disse space : exchange area between blood and hepatocytes, located between the hepatocytes and the wall of sinusoids.

Edema : abnormal accumulation of fluid in your arms, hands, legs, feet and face.

EIA : enzyme immunoassay. A test that detects the presence of antibodies to the hepatitis C virus, EIA is used for initial testing. Because false positive results are possible, supplementary tests (such as RIBA) are needed to confirm diagnosis.

ELISA : enzyme-linked immunosorbent assay - another name for the EIA test.

Enzyme : a cellular protein whose shape allows it to hold together several other molecules in close proximity to each other. In this way, enzymes are able to induce chemical reactions in other substances with little expenditure of energy and without being changed themselves. Basically, an enzyme acts as a catalyst.

Esophagus : a muscle lined tube extending from your throat to your stomach.

Factor V Leiden : this inherited anomaly of Factor V related to a single mutation. Factor V is one of the blood proteins involved in clotting. Factor V Leiden mutation induces a resistance of activated factor V to undergo degradation. This degradation is required for the control of the clotting process when it is no more needed. This mutation is common in Europe ( 5% of the population). People who have the factor V Leiden mutation are at a some what higher than average risk for a type of clot that forms in veins, but this disorder alone will not create thrombi. Factor V Leiden has to be associated to another prothrombic state for thrombosis to occur.

Fatigue : feeling extremely tired and lacking energy.

Fibrosis : the formation of fibrous tissue or scarring.

Fibrous septum (plur. septa) : abnormal extensions of normal fibrous tissue ( 'connective tissue' ), which take the form of fibrous walls. These walls disturb the normal hepatic structure. The cause of septa is either a prolonged hepatic inflammation or a blockade of hepatic vessels . Therefore, fibrous septa are both a cause and a result of a disorder of the hepatic microcirculation.

Fulminant : running a speedy course with rapid worsening.

Gallstones : solid lumps of cholesterol crystals or pigment material that form in the gall bladder or bile ducts. They may obstruct the flow of bile and cause pain.

Gamma-globulin : a type of protein in blood plasma that provides immunity to certain viruses, such as hepatitis A and hepatitis B (also called immune globulin or immunoglobulin).

Gastrointestinal (GI) : relating to the stomach and intestines.

Genotype : an identifiable strain of the hepatitis C virus. There are 11 major hepatitis C genotypes and more than 90 subtypes.

HCV : hepatitis C virus - the virus that causes hepatitis C.

HCV RNA : the actual viral material of hepatitis C.

Hemochromatosis : a disease in which too much iron is absorbed from the intestine and the excess iron accumulates in various organs. The liver is the first organ to store iron but when its storage capacity is exhausted, iron may accumulate in the heart, pituitary gland and elsewhere in the body. If untreated, damage to the liver, heart and pancreas may eventually cause death.

Hemoglobin : the component of red blood cells that carries oxygen.

Hemophilia : an inherited disease that affects mostly males and prevents normal blood clotting. It is treated by lifelong injections of a synthetic version of the clotting factor lacking in persons with the disease. The new recombinant clotting factor replaces the natural product, which was extracted from people's blood.

Hemophiliac : a person who has hemophilia.

Hepatic arterio venous fistula : Abnormality where a branch of the hepatic artery branch and a branch of a hepatic vein communicate permanently.

Hepatic artery aneurysm : localized lesion of the hepatic artery consisting in an abnormal bulge or "ballooning" in the wall of the artery. Common causes are infection, congenital defect or atheroma.

Hepatic artery thrombosis : the hepatic artery is blocked by a thrombus. This is generally caused by a prothrombic state.

Hepatic blood microcirculation  : these hepatic blood vessels are only visible under the microscope. This portion of the hepatic circulatory system includes hepatic arterioles, portal venules, hepatic venules, and sinusoids.

Hepatic veins thrombosis : hepatic veins are blocked by a thrombus. This term is synonymous to primary Budd Chiari syndrome. This condition is generally caused by a prothrombic state.

Hepatitis : inflammation (or swelling) of the liver. inflammation (ou gonflement) du foie. Elle peut être liée à une infection virale: hépatite A, hépatite B, hépatite C.

Hepatitis A : a liver disease caused by the hepatitis A virus and spread through contaminated food and water.

Hepatitis B : a liver disease caused by the hepatitis B virus and spread through direct contact with blood or body fluids or sexual contact with an infected person.

Hepatitis C : a liver disease caused by the hepatitis C virus (HCV) and spread through direct blood-to-blood contact with an infected person.

Hepatocellular carcinoma : liver cancer.

Hepatocycte : liver cells.

Hepatomegaly : enlarged liver.

Hepatoportal sclerosis : fibrous narrowing of the intrahepatic branches of the portal vein, in association with fibrous septa extending from the portal tracts. This term is almost synonymous with obliterative portal venopathy.

HIV : a disease in which the human immunodeficiency virus (HIV) weakens the person's immune system. HIV is the virus that causes AIDS (acquired immune deficiency syndrome).

Hyperglycemia : an abnormally high level of sugars in the blood.

Hypoglycemia : an abnormally low level of sugars in the blood.

Idiopathic cholangiopathy : local or extended disease of the intra or extra hepatic biliary tract, the cause of which has not been identified using currently available medical techniques.

Idiopathic portal hypertension : a portal hypertension in absence of cirrhosis or other know causes. The name of « non-cirrhotic intrahepatic portal hypertension » is also used for that entity.

Immune system : the natural defence mechanism in the body that reduces susceptibility to a disease.

Immunity : a body's resistance to the effects of a deleterious agent, such as a virus. A person may have developed immunity to one virus but not another.

Immunization : an injection with a vaccine that causes the body to develop immunity against a certain virus or bacterial infection.

Immunocompromised : used to describe people who lack normal natural levels of immunity. This could include people with HIV infection or people who are taking immunosuppressive drugs (such as transplant patients).

Immunoglobulin : a type of protein in blood plasma that provides immunity to certain viruses, such as hepatitis A and hepatitis B (also called gamma-globulin).

Incidence : the number of new cases of a disease occurring in a given population over a certain period of time.

Incubation period : the time it takes for the virus to develop sufficient copies of itself in a body before symptoms and signs of the disease occur and before it can be detected through blood tests.

Inherited antithrombin deficiencies : this inherited anomaly, due to numerous mutations of the antithrombin gene, results in a reduced concentration of antithrombin within the blood. Antithrombin is a natural anticoagulant necessary to inhibit the effect of thrombin, which is the main activator of coagulation. Thrombin derives from prothrombin, which allows the transformation of fibrogen from a liquid to a solid state, so called fibrin, which, in association with blood platelet may lead to the formation of thrombus. Inhibition of thrombin by antithrombin is required to control blood coagulation when coagulation is not or is no longer needed. Inherited antithrombin deficiency is a rare disease. It is a powerful prothrombotic state.

Inherited protein C deficiencies : this inherited anomaly, due to numerous mutations of the gene responsible for synthesizing protein C, results in a reduced concentration of protein C within the blood. Protein C is a natural anticoagulant necessary to destroy the activated coagulation factors. Protein C and protein S work together in this process. This destruction is necessary to stop the process of blood coagulation when it is no longer needed. Inherited protein C deficiency is a rare disease. It is a powerful prothrombotic state.

Inherited protein S deficiencies : this inherited anomaly, due to numerous mutations of the gene responsible for synthesizing protein S, results in a reduced concentration of protein S within the blood. Protein S is a natural anticoagulant necessary to destroy the activated coagulation factors. Protein C and Protein S work together in this process. This destruction is necessary to stop the process of blood coagulation when it is no longer needed. Inherited protein S deficiency is a rare disease. It is a powerful prothrombotic state.

In vitro : outside the living body and in an artificial environment.

In vivo : in the living body of a plant or animal.

Interferon : one of a number of antiviral proteins that modulate immune response. Interferon alpha (IFNa) is secreted by an infected cell and strengthens the defenses of nearby uninfected cells. A manufactured version of IFNa (trade names: Roferon, Intron A) is an HPB approved treatment for Kaposi's sarcoma, the hepatitis B virus and the hepatitis C virus. une des quelques protéines antivirales qui modulent la réponse immune. L'interféron alpha (IFNa) est sécrété par une cellule infectée et renforce les défenses des cellules avoisinantes non infectées. Une version manufacturée de l'IFNa (marques de commerce : Roferon, Intron A) est un traitement approuvé par la DGPS pour le sarcome de Kaposi, le virus de l'hépatite B et le virus de l'hépatite C. L'interféron est également utilisé dans certains cas de syndromes myeloprolifératifs (trhombocytémie, maladie de Vaquez). Les effets secondaires sont variables et très divers.

Irritable bowel syndrome : (spastic colon) a motility disorder involving the entire gastrointestinal tract, causing variable degrees of abdominal pain, constipation and/or diarrhea and abdominal bloating.

Ischemia : inadequate blood supply

Ischemic cholangiopathy : local or diffuse disease of the intra or extra hepatic biliary tract due to the lack of arterial flow toward the biliary tract. The cause can be damage to large hepatic arteries, or diffuse damage to the small biliary arteries that form the peribiliary plexus.

Jaundice : yellow discolouration of the skin and eyes as a result of a build-up of bilirubin in the blood. May be a symptom of many liver diseases.

Kayser-Fleischer rings : golden-brown rings in the corneas due to copper disposition in Wilson disease.

Kupffer cells : "scavenger" cells that remove foreign matter, worn-out blood cells and bacteria from the liver. amas solides de cristaux de cholestérol ou de matériel pigmenté qui se forment dans la vésicule biliaire ou les voies biliaires. Ils peuvent obstruer le débit de la bile et provoquer de la douleur.

Lipid : any of a heterogeneous group of fats and fat-like substances characterized by being water-insoluble.

Liver biopsy : a diagnostic procedure used to obtain a small amount of liver tissue, which can be examined under a microscope to help identify the cause or stage of liver disease. Under local anesthetic, a needle is inserted and a small piece of liver is removed.

Liver function tests : blood tests used to assess the general state of the liver or biliary system and to reflect the presence of damage or inflammation. Common LFTs include ALT, AST and bilirubin.

Liver Transplant : a life-saving operation to replace a diseased liver with a healthy, donated liver.

Mesenteric venous infarction : haemorrhagic necrosis (so called infarct or infarction) of a section of the intestine. The cause is a blockade of the upper or lower mesenteric vein.

Myeloproliferative diseases : these disorders are characterized by a disturbance in the regulation process of blood cell production which leads to an over production of red cells, leucocytes and platelets. Most of those diseases result from an acquired mutation of a protein named JAK II. This protein, present inside the blood cells, transmits the order to start or stop the process of blood cell production. The mutation initiates a permanent production of blood cells ( myeloproliferation ). Being acquired during life and affecting only the blood stem cell, this mutation is not transmitted to out springs. We don't understand very well why the myeloproliferative diseases are prothrombic states. Polycythemia vera, essential thrombocythemia and myelofibrosis with myeloid metaplasia are part of myeloproliferative diseases.

Mutation : the ability of a virus to change its outer coating and to therefore not be recognized and attacked by antibodies.

NAT : nucleic acid testing. Testing that allows direct detection of specific HCV RNA in serum, plasma or tissues, independent of the host's immune response. Viral nucleic acid detected in the plasma or serum reflects active HCV replication in the liver. NAT-based detection of HCV RNA is performed in two major ways. The most common is target amplification, an example of which is the polymerase chain reaction (PCR). The other major approach involves signal amplification and includes the branched chain DNA technique.

Nausea : feeling sick to your stomach and wanting to vomit.

Nodular regenerative hyperplasia : the abnormal formation of nodules of hepatocytes which in the normal state, are organized in rows. This change in the structure seems to be a reaction to an uneven blood perfusion to the hepatic parenchyma, whereby some areas are deprived from blood and thus atrophy, whereas other areas receive adequate blood flow and thus hypertrophy.

Non cirrotic intrahepatic block : due to internal lesion to the liver, the portal blood flow is blocked. The usual causes of such blockade is cirrhosis related to alcohol abuse, diabetes, obesity, viral hepatitis or hemochromatosis. In some cases, however the blockage is not due to cirrhosis. In that case the term non-cirrhotic intrahepatic block is used. The cause can be a blockade of the tiny hepatic veins ( veno-occlusive disease) or a change in the structure of the hepatic tissue which impairs the tiny liver vessels. This blockade will lead to portal hypertension. A number of diseases can lead to non cirrhotic intrahepatic block, though this is uncommon.

Non cirrhotic portal hypertension : portal hypertension not caused by cirrhosis or by a blockade in the portal or hepatic veins. This hypertension is linked to disorders affecting the microcirculation and generating a heterogeneity of the hepatic perfusion.

Nucleic acid : molecules in living cells, which carry hereditary information. The presence of DNA and RNA, the chief types of nucleic acid, allow cells to replicate themselves.

Nucleoside : a building block of nucleic acids. Nucleosides are nucleotides without the phosphate group.

Obliterative portal venopathy : a lesion which induces an obstruction of the portal venules inside the liver. These lesions are often associated with fibrous septa, sinusoidal dilatation and nodular regenerative hyperplasia. Prothrombic state and exposition to some toxic products (arsenic, vinyl chloride monomer, thorium sulfate) are known to be responsible for these lesions.

Paroxysmal nocturnal hemoglobinuria : it is an acquired blood disease characterized by a mutation in the blood stem cells. This mutation induces an excessive fragility of red blood the red blood cells resulting in their accelerated breakdown (hyperhemolysis). It also results in abnormal function of white blood cells (causing recurrent infections ); and abnormal function of platelets (causing thrombosis). The breakdown of the red cells releases haemoglobin which passes into the urine. The term "nocturnal" refers to the belief that haemolysis happens during sleep. The prothrombotic state in this disease is still not well understood.

PCR : polymerase chain reaction. PCR is a method to test for HCV RNA, the actual viral material of hepatitis C. There are two types of test for HCV RNA by PCR. Qualitative tests give a positive or negative result and are recommended for patients who are anti-HCV positive with normal ALT levels and to determine response to treatment. Quantitative tests give the viral concentration or viral load and are not routinely recommended for patients.

Pegylated interferon : a form of interferon that stays in the body longer. Pegylated interferon is created by attaching polymers to interferon. This allows the interferon to become more water-soluble and to remain inside the body longer, accounting for its enhanced activity. This reduces the frequency of injections. Pegylated interferon is under review for approval in Canada.

Peliosis hepatis : this disorder is characterized by the presence of blood-filled cavities in the liver (1 mm to several cm in diameter). Due to inhomogeneous enlargement of the hepatic sinusoid. The cavities are bordered by hepatocytes. Peliosis hepatis can result from infections (for example tuberculosis, pyelonephritis, cat-scratch disease), drugs (azathioprine, androgens,.... ), tumours.....

Peribiliary plexus : the network of arterioles and capillaries coming out from the hepatic arteries and supplying the bile ducts.

Perisinusoidal fibrosis : collagen fibers are deposited in the Disse space, which can be responsible for portal hypertension. Vitamin A intoxication is frequently at the origin of this situation.

Platelet : fragments of blood cells that are necessary for blood clotting (coagulation). Platelets are released when damage occurs to a blood vessel. By forming into clots, they stem the flow of blood from the damaged blood vessel.

Polymerase : any of several enzymes that catalyze the formation of DNA or RNA using preexisting DNA or RNA as a template (pattern).

Porphyria : the inability of cells to convert porphyrins to heme in a normal manner. Porphyrins are chemical compounds that are stepping stones along the pathway that leads to the formation of heme in humans and to chlorophyll in plants.

Portal cavernoma : in case of a blockage of the portal vein, a mass forms with new and numerous collateral veins linking the portal venous led upstream from the obstacle to the portal venous led downstream; this mass is called a cavernoma. The cavernoma directs again, although partially, the portal flow toward the liver. Because the resistance to blood flow in these collateral veins is increased as compared to a normal portal vein, there is portal hypertension. Thrombosis is the main cause for cavernoma.

Portal hypertension : an increase in pressure in the portal venous system to a level higher than 10 mm Hg, or an increase in pressure to more than 5 mm Hg above the pressure inside of right atrium. This increase is the consequence of a blockade to the portal flow. Blockade can be upstream or downstream to the liver, or internal to the liver.

Portal thrombosis : the portal vein or its right or left branch is blocked by a thrombus. This is generally caused by a prothrombic state.

Portal vein : this large vein routes blood from the abdominal organs into the liver. It is formed by the superior mesenteric and splenic veins behind the pancreas. It ascends in front of the inferior vena cava and divides into right and left branches that ramify within the liver.

Prognosis : prediction as to the probable outcome of a disease. Protease inhibitor a type of antiviral drug that acts by inhibiting the virus' protease enzyme. This prevents the virus from replicating itself.

Protease : an enzyme that breaks down proteins, including viral proteins.

Prothrombic states : disorders which favours the formation of thrombi. The most frequent prothrombic states involved in vascular liver diseases are either acquired or inherited. Acquired states include myeloproliferative diseases and antiphospholipid syndrome, paroxysmal nocturnal hemoglobinuria, Behcet's disease, the inflammatory bowel diseases, oral contraceptives, pregnancy, severe inflammatory states or cancer. Inherited states consist of factor V Leiden, prothrombin gene mutation, inherited deficiencies in protein C or S or in antithrombin.

Prothrombin's gene mutation : inherited defect due to a specific mutation in prothrombin gene. Prothrombin is one of the blood proteins necessary for clotting. This mutation initiates an increase of prothrombin in the blood. It is a weak prothrombic state. Alone, this disorder will not create thrombi. Other prothrombic states have to be associated to this anomaly for thrombosis to develop.

Pruritus : itching.

Quasispecies : closely related variants of a single genotype within a single individual, which arise from mutations that occur during viral replication. The quasispecies may have an impact on how the virus reacts in an individual and on the natural history of the infection.

Radioisotope scan : a special test that tags blood cells with radioactivity so that they can be tracked as they move throughout the body.

RIBA : recombinant immunoblot assay is a supplementary test used to confirm findings when an EIA test is positive. Measures the presence of various antibodies to hepatitis C in the blood.

Ribavirin : one of a group of drugs called nucleoside analogues that prevent viruses from multiplying. Ribavirin is used in combination with interferon alfa-2b in the treatment of hepatitis C.

Seroconversion : the development of antibodies to a particular antigen.

Serologic test : any of a number of tests done using the clear portion of blood. Often refers to a test that determines the presence of antibodies to antigens such as viruses.

Sinusoidal dilatation :involvement of hepatic microcirculation related to dilatation of sinusoids. Sinusoidal dilatation can be secondary to down stream obstruction (of hepatic veins or inferior vena cava, or to the congestion resulting from heart disease). Other causes of sinusoidal dilatation, which are not related to an obstacle, are numerous but rare, including Crohn's disease, severe infection, and prothrombotic states. In many patients, the cause of sinusoidal dilatation cannot be identified. Sinusoidal dilatation and perisinusoidal fibrosis are often found in association.

Sinusoidal obstruction syndrome : a disease where the sinusoidal endothelial cells are damaged, leading them to necrosis and their passive transport to the walls of the hepatic venules where they are blocked. The main factors responsible for this condition are: ionizing radiation, cancer chemotherapy, marrow bone graft conditioning and plant components (pyrrolizide alkaloids ).

Sinusoids : capillaries are the smallest of the body's blood vessels. They connect arterioles and venules. Venules converge to create veins. Capillaries in the liver are called sinusoids. The thinness of capillary walls allows exchanges between blood and hepatic cells. These capillaries allow the passage of liquid but not of blood cells. This feature distinguishes them from

Spider nevi : asymptomatic, spider-like marks that may develop in patients with advanced cirrhosis of the liver. The mark consists of a central arteriole, radiating from which are numerous small vessels resembling a spider's legs. Common sites are the necklace area, face, forearms and the back of the hands. (Also called vascular spiders, arterial spiders, spider telangiectasis or spider angioma.)

Spleen :a large organ situated in the upper part of the abdominal cavity on the left side. The spleen breaks down red blood cells and sets free hemoglobin, which the liver then converts into bilirubin. In addition, the spleen performs many more important functions.

Splenic vein trhombosis : the splenic vein is blocked by a thrombus. This is generally caused by a prothrombic state.

Splenomegaly : an enlarged spleen.

Steatorrhea : decreased absorption of dietary fats, resulting in their passage to the distal bowel which causes foul-smelling and floating stool; can be caused by deficiency of bile salts.

Steroid : a member of a large family of structurally-similar lipid molecules. Different classes of steroids perform different functions. Anti-inflammatory steroids can reduce swelling, pain and inflammation.

Superior mesenteric vein : this blood vessel drains blood from the small intestine. It joins with the splenic vein to form the portal vein.

Superior mesenteric vein thrombosis : the superior mesenteric vein is blocked by a thrombus. This is generally caused by a prothrombic state.

Teratogenicity : tendency to produce birth defects. Teratogenicity is a potential side effect of some drugs, including ribavirin.

Thrombosis : the entity corresponding to the formation a thrombus inside a blood vessel. A thrombus can dissolve or undergo tranformation into retractile scar tissue. This affection is generally related to a prothrombic state.

Thrombus (plur. Thrombi) : a solid mass of blood components (platelets and fibrin). Its natural function is to block an opening in the vascular system. In an abnormal situation, a thrombus can start without any vascular opening. The vessel is then blocked, which will disturb or stop the blood flow.

Titre : a laboratory measurement of the concentration of a given compound in solution. (Also spelled "titer".)

Ultrasound : a non-invasive way to examine soft organs that uses sound waves rather than light rays. Ultrasounds of the abdominal cavity are one way to examine the size and state of the liver.

Vaccine : a solution of killed or inactive viruses or bacteria or synthetically, genetically engineered antigenic material. Usually administered by injection, a vaccine can stimulate an immune response and thus give a person protection against contracting a disease. Currently there is no vaccine against hepatitis C.

Varices : large, swollen blood vessels in the stomach and esophagus. In people with severe liver damage the normal flow of blood through the liver is blocked. Blood from the intestines is then rerouted around the liver, primarily through the small blood vessels in the stomach and esophagus. These can become enlarged and swollen (varices) and eventually rupture, causing internal bleeding.

Veno occlusive disease : disease resulting from a blockade of the small hepatic veins in the liver, without obstruction of the large hepatic veins .

Virus : a tiny microorganism, smaller than bacteria, which cannot replicate itself without a host and can cause sickness in humans that cannot be treated with antibiotics.

Copyright Canadian Liver Foundation
Nos remerciements à la Canadian Liver Foundation

______________________________________________________

Words to understand and exchange

Enrichment of the Glossary of the vascular diseases of the liver
By members of the Scientific Council of the AMVF

DR. Aurelie PLESSIER and PR. Dominique VALLA of the Center of Reference of the Vascular Diseases of the Liver, Beaujon Hospital, 92-Clichy

Antiphospholipid syndrome : A disorder characterized by the autoimmune production of antibodies against cell membrane constituents (proteins and phospholipids) and by venous or arterial thrombosis, or recurrent abortions. The cause of this syndrome and the mechanism of the prothrombic state are not known.

Arterioportal fistula : Abnormality where a hepatic artery and a portal vein communicate permanently. Causes can be congenital, traumatic or surgical. Occasionally, the fistula appears to have developed spontaneously.

Behcet's disease : An inflammatory disease of unknown origin, seldom seen in the West, well known in Turkey and North Africa. The clinical spectrum includes involvement of veins, joints, skin, eyes and gastrointestinal tract. Inferior vena cava thrombosis is frequent. In this disease, the cause of the prothrombic state is still not understood.

Budd-Chiari syndrome : The condition results from the obstruction of the hepatic venous outflow tract, when the obstruction lies between the small intrahepatic veins and the termination of inferior vena cava in to the right atrium. There are two categories of Budd- Chiari syndrome. The first one, so called primary Budd-Chiari syndrome, covers the blockade of the venous system due to thrombosis or to a narrowing of the venous wall, whether they are focal or diffuse . In this category Budd Chiari syndrome is explained by a prothrombic state. In the second category, so called secondary Budd-Chiari syndrome, tumours, parasites or extrinsic compression are responsible for the blockade rather than a primary disease of the veins.

Congenital portacaval shunt : Abnormal passage of the blood from a portal vein to a vein draining into inferior vena cava due to a congenital defect joining the two veins. This anomaly is present from birth.

Congestion : Abnormal accumulation of blood inside vessels, tissues or organs. A downstream obstacle generating a stasis can explain the congestion. Other reasons can be a congenital vessel dilatation or abnormal exit of blood cells outside damaged vessels.

Disse space : Exchange area between blood and hepatocytes, located between the hepatocytes and the wall of sinusoids.

Factor V Leaden : This inherited anomaly of Factor V related to a single mutation. Factor V is one of the blood proteins involved in clotting. Factor V Leiden mutation induces a resistance of activated factor V to undergo degradation. This degradation is required for the control of the clotting process when it is no more needed. This mutation is common in Europe ( 5% of the population). People who have the factor V Leiden mutation are at a some what higher than average risk for a type of clot that forms in veins, but this disorder alone will not create thrombi. Factor V Leiden has to be associated to another prothrombic state for thrombosis to occur.

Fibrous septum (plur. septa) : Abnormal extensions of normal fibrous tissue ( 'connective tissue' ), which take the form of fibrous walls. These walls disturb the normal hepatic structure. The cause of septa is either a prolonged hepatic inflammation or a blockade of hepatic vessels . Therefore, fibrous septa are both a cause and a result of a disorder of the hepatic microcirculation.

Hepatic arteriovenous fistula : Abnormality where a branch of the hepatic artery branch and a branch of a hepatic vein communicate permanently.

Hepatic artery aneurysm : Localized lesion of the hepatic artery consisting in an abnormal bulge or "ballooning" in the wall of the artery. Common causes are infection, congenital defect or atheroma.

Hepatic artery thrombosis : The hepatic artery is blocked by a thrombus. This is generally caused by a prothrombic state.

Hepatic microcirculation : These hepatic blood vessels are only visible under the microscope. This portion of the hepatic circulatory system includes hepatic arterioles, portal venules, hepatic venules, and sinusoids.

Hepatic vein thrombosis : Hepatic veins are blocked by a thrombus. This term is synonymous to primary Budd Chiari syndrome. This condition is generally caused by a prothrombic state.

Hepatoportal sclerosis : Fibrous narrowing of the intrahepatic branches of the portal vein, in association with fibrous septa extending from the portal tracts. This term is almost synonymous with obliterative portal venopathy.

Idiopathic cholangiopathy : Local or extended disease of the intra or extra hepatic biliary tract, the cause of which has not been identified using currently available medical techniques.

Idiopathic portal hypertension : A portal hypertension in absence of cirrhosis or other know causes. The name of « non-cirrhotic intrahepatic portal hypertension » is also used for that entity.

Inherited antithrombin deficiency : This inherited anomaly, due to numerous mutations of the antithrombin gene, results in a reduced concentration of antithrombin within the blood. Antithrombin is a natural anticoagulant necessary to inhibit the effect of thrombin, which is the main activator of coagulation. Thrombin derives from prothrombin, which allows the transformation of fibrogen from a liquid to a solid state, so called fibrin, which, in association with blood platelet may lead to the formation of thrombus. Inhibition of thrombin by antithrombin is required to control blood coagulation when coagulation is not or is no longer needed. Inherited antithrombin deficiency is a rare disease. It is a powerful prothrombotic state.

Inherited protein C deficiency : This inherited anomaly, due to numerous mutations of the gene responsible for synthesizing protein C, results in a reduced concentration of protein C within the blood. Protein C is a natural anticoagulant necessary to destroy the activated coagulation factors. Protein C and protein S work together in this process. This destruction is necessary to stop the process of blood coagulation when it is no longer needed. Inherited protein C deficiency is a rare disease. It is a powerful prothrombotic state.

Inherited protein S deficiency : This inherited anomaly, due to numerous mutations of the gene responsible for synthesizing protein S, results in a reduced concentration of protein S within the blood. Protein S is a natural anticoagulant necessary to destroy the activated coagulation factors. Protein C and Protein S work together in this process. This destruction is necessary to stop the process of blood coagulation when it is no longer needed. Inherited protein S deficiency is a rare disease. It is a powerful prothrombotic state.

Ischemia : Inadequate blood supply

Ischemic cholangiopathy : Local or diffuse disease of the intra or extra hepatic biliary tract due to the lack of arterial flow toward the biliary tract. The cause can be damage to large hepatic arteries, or diffuse damage to the small biliary arteries that form the peribiliary plexus.

Mesenteric venous infarction : Haemorrhagic necrosis (so called infarct or infarction) of a section of the intestine. The cause is a blockade of the upper or lower mesenteric vein.

Myeloproliferative diseases : These disorders are characterized by a disturbance in the regulation process of blood cell production which leads to an over production of red cells, leucocytes and platelets. Most of those diseases result from an acquired mutation of a protein named JAK II. This protein, present inside the blood cells, transmits the order to start or stop the process of blood cell production. The mutation initiates a permanent production of blood cells ( myeloproliferation ). Being acquired during life and affecting only the blood stem cell, this mutation is not transmitted to out springs. We don't understand very well why the myeloproliferative diseases are prothrombic states. Polycythemia vera, essential thrombocythemia and myelofibrosis with myeloid metaplasia are part of myeloproliferative diseases.

Nodular regenerative hyperplasia : The abnormal formation of nodules of hepatocytes which in the normal state, are organized in rows. This change in the structure seems to be a reaction to an uneven blood perfusion to the hepatic parenchyma, whereby some areas are deprived from blood and thus atrophy, whereas other areas receive adequate blood flow and thus hypertrophy.

Non cirrhotic intrahepatic block : Due to internal lesion to the liver, the portal blood flow is blocked. The usual causes of such blockade is cirrhosis related to alcohol abuse, diabetes, obesity, viral hepatitis or hemochromatosis. In some cases, however the blockage is not due to cirrhosis. In that case the term non-cirrhotic intrahepatic block is used. The cause can be a blockade of the tiny hepatic veins ( veno-occlusive disease) or a change in the structure of the hepatic tissue which impairs the tiny liver vessels. This blockade will lead to portal hypertension. A number of diseases can lead to non cirrhotic intrahepatic block, though this is uncommon.

Non cirrhotic portal hypertension : Portal hypertension not caused by cirrhosis or by a blockade in the portal or hepatic veins. This hypertension is linked to disorders affecting the microcirculation and generating a heterogeneity of the hepatic perfusion.

Obliterative portal venopathy : A lesion which induces an obstruction of the portal venules inside the liver. These lesions are often associated with fibrous septa, sinusoidal dilatation and nodular regenerative hyperplasia. Prothrombic state and exposition to some toxic products (arsenic, vinyl chloride monomer, thorium sulfate) are known to be responsible for these lesions.

Paroxysmal nocturnal hemoglobinuria : It is an acquired blood disease characterized by a mutation in the blood stem cells. This mutation induces an excessive fragility of red blood the red blood cells resulting in their accelerated breakdown (hyperhemolysis). It also results in abnormal function of white blood cells (causing recurrent infections ); and abnormal function of platelets (causing thrombosis). The breakdown of the red cells releases haemoglobin which passes into the urine. The term "nocturnal" refers to the belief that haemolysis happens during sleep. The prothrombotic state in this disease is still not well understood.

Peliosis hepatis : This disorder is characterized by the presence of blood-filled cavities in the liver (1 mm to several cm in diameter). Due to inhomogeneous enlargement of the hepatic sinusoid. The cavities are bordered by hepatocytes. Peliosis hepatis can result from infections (for example tuberculosis, pyelonephritis, cat-scratch disease), drugs (azathioprine, androgens,.... ), tumours.....

Peribiliary plexus : The network of arterioles and capillaries coming out from the hepatic arteries and supplying the bile ducts.

Perisinusoidal fibrosis : Collagen fibers are deposited in the Disse space, which can be responsible for portal hypertension. Vitamin A intoxication is frequently at the origin of this situation.

Portal cavernoma : In case of a blockage of the portal vein, a mass forms with new and numerous collateral veins linking the portal venous led upstream from the obstacle to the portal venous led downstream; this mass is called a cavernoma. The cavernoma directs again, although partially, the portal flow toward the liver. Because the resistance to blood flow in these collateral veins is increased as compared to a normal portal vein, there is portal hypertension. Thrombosis is the main cause for cavernoma.

Portal hypertension : An increase in pressure in the portal venous system to a level higher than 10 mm Hg, or an increase in pressure to more than 5 mm Hg above the pressure inside of right atrium. This increase is the consequence of a blockade to the portal flow. Blockade can be upstream or downstream to the liver, or internal to the liver.

Portal thrombosis : The portal vein or its right or left branch is blocked by a thrombus. This is generally caused by a prothrombic state.

Portal vein : This large vein routes blood from the abdominal organs into the liver. It is formed by the superior mesenteric and splenic veins behind the pancreas. It ascends in front of the inferior vena cava and divides into right and left branches that ramify within the liver.

Portal venous system : The portal venous system is responsible for directing blood from the gastrointestinal tract, spleen and pancreas to the liver. This venous system is very specific in the body, as by contrast with other venous systems, both ends of the portal venous system are connected to capillary networks: upstream, capillaries from the spleen, the pancreas and the gastrointestinal tract; down stream, from the hepatic sinusoids. The superior mesenteric vein, inferior mesenteric vein and the splenic vein converge to form the trunk of the portal vein which then separates into the right and left portal vein before ending up in capillaries in the liver. The portal vein system is complementary to the hepatic artery and serves to supply the liver with blood.

Prothrombin gene mutation : Inherited defect due to a specific mutation in prothrombin gene. Prothrombin is one of the blood proteins necessary for clotting. This mutation initiates an increase of prothrombin in the blood. It is a weak prothrombic state. Alone, this disorder will not create thrombi. Other prothrombic states have to be associated to this anomaly for thrombosis to develop.

Prothrombotic states : Disorders which favours the formation of thrombi. The most frequent prothrombic states involved in vascular liver diseases are either acquired or inherited. Acquired states include myeloproliferative diseases and antiphospholipid syndrome, paroxysmal nocturnal hemoglobinuria, Behcet's disease, the inflammatory bowel diseases, oral contraceptives, pregnancy, severe inflammatory states or cancer. Inherited states consist of factor V Leiden, prothrombin gene mutation, inherited deficiencies in protein C or S or in antithrombin.

Sinusoidal dilatation : Involvement of hepatic microcirculation related to dilatation of sinusoids. Sinusoidal dilatation can be secondary to down stream obstruction (of hepatic veins or inferior vena cava, or to the congestion resulting from heart disease). Other causes of sinusoidal dilatation, which are not related to an obstacle, are numerous but rare, including Crohn's disease, severe infection, and prothrombotic states. In many patients, the cause of sinusoidal dilatation cannot be identified. Sinusoidal dilatation and perisinusoidal fibrosis are often found in association.

Sinusoidal obstruction syndrome : A disease where the sinusoidal endothelial cells are damaged, leading them to necrosis and their passive transport to the walls of the hepatic venules where they are blocked. The main factors responsible for this condition are: ionizing radiation, cancer chemotherapy, marrow bone graft conditioning and plant components (pyrrolizide alkaloids ).

Sinusoids : Capillaries are the smallest of the body's blood vessels. They connect arterioles and venules. Venules converge to create veins. Capillaries in the liver are called sinusoids. The thinness of capillary walls allows exchanges between blood and hepatic cells. These capillaries allow the passage of liquid but not of blood cells. This feature distinguishes them from the other capillaries of the body.

Splenic vein thrombosis : The splenic vein is blocked by a thrombus. This is generally caused by a prothrombic state.

Superior mesenteric vein : This blood vessel drains blood from the small intestine. It joins with the splenic vein to form the portal vein.

Superior mesenteric vein thrombosis : The superior mesenteric vein is blocked by a thrombus. This is generally caused by a prothrombic state.

Thrombosis : The entity corresponding to the formation a thrombus inside a blood vessel. A thrombus can dissolve or undergo tranformation into retractile scar tissue. This affection is generally related to a prothrombic state.

Thrombus (plur.Thrombi) : A solid mass of blood components (platelets and fibrin). Its natural function is to block an opening in the vascular system. In an abnormal situation, a thrombus can start without any vascular opening. The vessel is then blocked, which will disturb or stop the blood flow.

Veno occlusive disease : Disease resulting from a blockade of the small hepatic veins in the liver, without obstruction of the large hepatic veins .


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